This application is based on and claims priority under 35 U.S.C. xc2xa7119 with respect to Japanese Application No. 2000-070339 filed Mar. 14, 2000, the entire content of which is incorporated herein by reference.
1. Field of the Invention
The present invention is directed to an open/close control device for movable lids such as a sunroof panel and a power-operated window pane which are provided at vehicular openings, respectively.
2. Prior Art
Sometimes an automotive vehicle is provided with an open/close control device which moves, in response to a driver""s switch manipulation, a sunroof panel or a power-operated window pane for opening/closing an opening of an automotive vehicle. For example, Japanese Patent Publication No.Hei.5(1993)-25686 discloses a sunroof open/close control device which moves a sunroof panel to tilt open/close and to slide open/close. In addition, a recent open/close control device has a sandwiched condition prevention function to stop or reverse a sunroof panel or a power-operated window pane when something, such as a part of human body or an object, is held between the vehicular opening and a moving sunroof panel or a moving power-operated window pane.
In the open/close control device of the type for controlling movement of a lid, such as a sunroof panel or a power-operated window pane, detecting a position of the lid is required. A conventional lid position detection method is to count a number of edges of a pulse train signal which is output from a Hall-IC (i.e. rotation number sensor) which senses a magnet rotating together with an output shaft of an electric motor. With this method, an ON-and-OFF condition of a relay is monitored. The relay controls normal direction rotation, reverse direction rotation, and termination of the electric motor. A lid position detection is made by clocking a position counter based upon the change in the ON-and-OFF condition of the relay. In addition, as Japanese Patent laid-open Print No.Hei.10(1998)-109534 discloses, a lid position detection device is provided which operates without employing a Hall-IC. In this lid position detection device, detecting the position of the lid (i.e. sunroof panel) is made by counting the number of edges of a ripple pulse signal which is obtained by shaping a signal detected from a current flowing through a DC motor. In this device, in order to recognize the direction of the lid, the foregoing concept is employed.
However, in the conventional lid position detecting method or device, the timing of stopping or reversing the lid (i.e. sunroof panel or power-operated window pane) is determined upon issue of a motor stop instruction or a motor reverse instruction by monitoring the change of ON-and-OFF condition of the relay. Thus, after recognition of the actual termination or reverse rotation of the motor, the motor continues to rotate due to inertia for a predetermined period of time. Sometimes the resultant rotation number may not be reflected on the indication of the position counter. In addition, an unexpected noise which is superposed on the pulse train signal may be mistakenly counted.
In view of such circumstances, conventionally, in addition to the sensor or Hall-IC which generates the pulse train signal, a position detection switch is provided which detects absolute position of the sunroof panel such that a signal issued from the position detection switch corrects or amends the indication of the position counter which indicates the position of the sunroof panel. In particular, a position correction sensor, such as the position detection switch, is frequently placed away from the motor and/or control unit. Thus, a harness, which is of a long length, is required in addition to the position detection sensor. Thus, separate preparations of the sensor such as Hall-ICs and the position correction sensor increase the number of parts (i.e. sensors and harness) to be mounted to the vehicle body. Therefore, the open/close control device is made complex and large-sized, the contents of the control becomes very complex, and the production productivity is lowered due to increasing the number of parts to be assembled.
Thus, a need exists to provide, for overcoming the aforementioned problems, an open/close control device for a movable lid which is highly precise in position detection of the lid using only a sensor which issues a pulse train signal in response to the rotation number of a motor.
The present invention has been developed to satisfy the request noted above. A first aspect of the present invention provides an open/close control device for a movable lid which opens and closes an opening. The control device includes a) a motor for driving the lid, b) a pair of rotation number detection sensors which generate pulse train signals, respectively, the pulse train signals being of a frequency which is in proportion to a rotation number of the motor but having a different phase, and c) position detection means for determining a movement direction of the lid and for detecting a position of the lid based on the pulse train signals, respectively. The position detection means is operated to continue the detection of the position of the lid as long as the motor is rotated by inertia after the motor is deenergized for stopping the movement of the lid.
In accordance with the first aspect of the present invention, on the basis of the pulse train signals issued from the pair of the rotation number sensors, respectively, which are out of phase, the direction of the movement of the lid is determined and the current position of the lid is detected. Even though an order is issued to stop driving the motor (e.g. a switch of the motor is shifted to a stop position), position detection continues as long as the motor is believed to rotate due to inertia. Thus, it is possible to precisely detect the position of the lid.
A second aspect of the present invention is to provide an open/close control device as a limited version of the first aspect, wherein the position detection means continues to detect the position of the lid in a positive direction of the motor unless a movement in a reverse direction of the lid is detected, when the motor is driven to move the lid in the reverse direction.
In accordance with the second aspect of the present invention, in addition to the operation and advantages in the first aspect, even though the motor is driven to reverse the direction of movement of the lid, the position detection means continues to detect the position assuming that the lid is moving in a positive direction as long as the reverse movement of the lid is not detected. Upon detection of the reverse movement of the lid, the position counting is initiated in the reverse direction.
A third aspect of the present invention is to provide an open/close control device for a movable lid which opens and closes an opening. The control device includes a) a motor for driving the lid, b) a pair of rotation number detection sensors which generate pulse train signals, respectively, the pulse train signals being of a frequency which is in proportion to a rotation number of the electric motor having a different phase, and c) position detection means for determining a movement direction of the lid and for detecting a position of the lid based on the pulse train signals, respectively. The position detection means determines that the pulse train signal, which is used for detecting the reverse movement of the lid, is a noise when a) the motor is ordered to stop or to move in a positive direction and b) the reverse movement of the lid is detected by the position detection means.
In accordance with the third aspect of the present invention, based on the pulse train signals issued from the pair of the rotation number sensors, respectively, which are out of phase, the direction of the movement of the lid is determined and the current position of the lid is detected. If the reverse movement of the lid is found despite no command to the motor for reversing the direction of movement of the lid, the pulse train signal used for the reverse detection is treated as a noise. Thus, determining the precise position of the lid can be made.
A fourth aspect of the present invention is to provide an open/close control device for a movable lid which opens and closes an opening. The control device includes a) a motor for driving the lid, b) a pair of rotation number detection sensors which generates pulse train signals, respectively, the pulse train signals being in proportion to a rotation number of the electric motor but being out of phase, and c) position detection means for determining a movement direction of the lid and for detecting a position of the lid based on the pulse train signals, respectively. The position detection means includes clocking means for counting a cycle of the pulse train signal. The position detection means operates such that the pulse train signal is treated as a noise when the cycle of the pulse train signals is found to be smaller than a predetermined value.
In accordance with the fourth aspect of the present invention, based on the pulse train signals issued from the pair of the rotation number sensors, respectively, which are out of phase, the direction of movement of the lid is determined and the current position of the lid is detected. The pulse train signal is treated as a noise when the cycle of the pulse train signal, which is measured by the clock means, is found to be less than a predetermined value. Thus, it is possible to avoid an unexpected indication of the position of the lid caused by noise or by mistake, resulting in very precise detection of the position of the lid.
A fifth aspect of the present invention is to provide an open/close control device as an improved version of any one of the first, second, third, and fourth aspects of the present invention, which further comprises a sandwiched condition detection means for detecting a sandwiched condition caused between the lid and an object based on the pulse train signal.
In accordance with the fifth aspect of the present invention, in addition to the operation and advantages of any one of the first aspect, second aspect, third aspect, and fourth aspect, based on the pulse train signal, the sandwiched condition detection means detects a sandwiched condition which makes it possible to use the rotation number sensor instead of preparing a sensor for only detecting the sandwiched condition.
A sixth aspect of the present invention is to provide an open/close control device as a limited version of the fifth aspect, wherein the lid is a sunroof panel of a vehicle which opens and closes an opening of a vehicle roof.
In accordance with the sixth aspect of the present invention, the sandwiched condition can be established.
A seventh aspect of the present invention is to provide an open/close control device as a limited version of the fifth aspect, wherein the sandwiched condition detection means recognizes the sandwiched condition if a subsequent edge of the pulse train signal fails to appear within a time duration after a detection of an edge of the pulse train signal.
In accordance with the seventh aspect, even though the cycle of the pulse train signal can not be obtained due to a fully locked condition of the electric motor, the sandwiched condition can be accurately detected.